Die assembly for making tau-head nails



Nov. 5, 1963 A. J. PlRC DIE ASSEMBLY FOR MAKING T-HEAD NAILS Filed Oct. 12, 1960 INVENTOR ANTHONY J. P/Rc 91% Affgrney United States Patent 3,109,187 DIE ASSEMBLY FDR MAKING T-HEAD NAILS Anthony J. Pirc, Juliet, 11L, assignor to United States Steel Corporation, a corporation of New Jersey Filed Oct. 12, 1960, Ser. No. 62,277 2 Claims. (CI. 10-43) This invention relates to a die assembly for making T-head nails and more particularly for making T-head nails in which the shank diameter is the same as the width of the head of the nail. T-head nails are made in various ways and particularly by stamping the nails out of metal sheet or by forming the nail from wire wherein the head is shaped by a hammer die. In many cases the T-head nails or tacks are cemented together in strip form as shown in Krantz Patent No. 2,294,463 dated September l, 1942, for use in a driving tool. This requires accuracy in the dimensions of the nail and freedom from burrs, particularly in the nail head. In the prior practices it was difiicult to consistently produce T-head nails of the required quality without processing them by a burr removing operation. This was expensive and not completely satisfactory.

It is therefore an object of my invention to provide apparatus for making T-head nails from wire in a modified conventional nail making machine in which the nails formed are accurate in dimension and tree of burrs.

This and other objects will be more apparent after referring to the following specification and attached drawings, in which:

FIGURE 1 is an elevation of my device in which the parts are shown in inoperative position;

FIGURE 2 is a view taken on the line 11-11 of FIG- URE 1;

FIGURE 3 is a view, similar to FIGURE 1, but with certain parts shown in operative position;

FIGURE 4 is a perspective view showing one closing die and the hammer die; and

FIGURE 5 is a perspective view of a formed T-head nail.

Referring more particularly to the drawings the reference numeral 2 indicates a fixed gripping die and the reference numeral 4 a gripping die movable transversely toward and away from the die 2. The dies 2 and 4 are mounted in a conventional nail making machine in the usual manner. One such machine is shown in Sleeper Patent No. 1,479,877 dated January 8, 1924. The die 2 includes a body portion 5 made of tool steel and having a tungsten carbide insert 6 therein on the end facing die 4. The insert 6 has a projection 8 thereon with a longitudinal groove 10 therein. The projection '8 terminates short of the top of the die a distance greater than the thickness T of the head H of nail N.- The groove 10 is preferably serrated as shown with the depth of the groove to the bottom of the serrations being slightly less than the radius of wire W from which the nail is formed. The wire W forms the shank S of the nail N so that the diameters of the wire and shank are the same. The outer surface of the projection 8 is spaced from surface 12 of insert 6' a distance substantially equal to the depth of groove 19. A semi-conical opening 14 is provided on the bot-tom of the die 2 so as to guide the wire W into the groove 10. The die 4 has a body portion 16 made of tool steel with a tungsten carbide insert 18 therein which is identical to insert 6. Cutter dies 20 are mounted above the gripping dies 2 and 4 as shown and are supported and reciprocated as in the above mentioned Sleeper patent. A hammer die 22 is mounted above the gripping dies 2 and 4 with its axis in alignment with the center of radius of groove 10. The die 22 includes a body portion 24 made of tool steel and a tungsten carbide insert 3 ,109,187 Patented Nov. 5, 1963 26. The tungsten carbide insert 26 includes a guide portion 28 and a hammer portion 30 with the guide portion extending beyond the hammer portion toward the gripping dies 2 and 4. The guide portion 28- has a cross section which increases in width from the gripping die end thereof to a maximum width equal to the width W of the nail head. As shown in the drawings this is done by having the bottom of the guide portion semi-circular in shape. The hammer portion 30 has a transverse fiat surface 32 which is at least as long as the length L of the nail head H. If desired a guide portion may be provided on each side of the hammer portion 30. The hammer 22 is supported and moved longitudinally toward and away from the dies 2 and *4 in the usual manner as in the Sleeper patent mentioned above. The wire W is gripped in the usual feeder 34 and is fed in a conventional manner such as in the Sleeper patent. While the pants are described with the wire W being :fed vertically upwardly it will be understood that the wire may be ted horizontally since the direction of teed has nothing to do with the present invention.

In operation, with the dies 4 and 20 retracted as shown in FIGURES 1 and 2, the wire W is fed between the dies 2 and 4 until a sufiicient amount of wire extends above the projections 8 to form the head H of the nail. For the purpose of speed in forming nails this extension must be to the top of the gripping dies or the plane of the bottom of the cutter dies 20. The dies 2 and 4 are then brought together to firmly grip the wire W therebetween as shown in FIGURE 3. In this position the taces of the projections of inserts l6 and 18 will be almost touching, there being preferably a few thousandths of an inch clearance. Also in this position there will be a recess 36 between the dies 2 and 4 at the end adjacent the hammer 22. This recess 36 forms the head of a T shaped cavity. The width of the recess 36 is equal to the width W of the nail head and its length is greater than the length L of the nail head. The hammer 22 is then fed downwardly with the guide portion 28 first entering, the recess 36. This is necessary because the width of the hammer portion 30 is substantially equal to the width of recess 36 and there is a certain amount of play in the power stroke of the hammer so that the hammer center line does not always coincide exactly with the center line of the wire positioned between the dies .2 and 4. While the guide could be eliminated it the width of recess 36 were made sufliciently wider than the thickness of hammer portion 30 this cannot be done because fins would be formed on the nail head. Thus only suflicient clearance is provided to enable the hammer portion 30 to move downwardly in the recess 36 when exactly centered therein. When the hammer surface 3 2 hits the end of the nail N it drives it downwardly in the recess 36 to form the head portion of the nail. After the head is termed movable die 4 and hammer 22 are retracted and the wire W [is advanced to the position shown in FIGURE 3. The die '4 is then advanced into gripping position and cutter dies 20 come together to cut the finished nail from the wire and form the point thereon. After the wire is out the cutter dies 20 are retracted and the hammer 22 is advanced to again form a head of another nail.

While one embodiment of my invention has been shown and described, it will be apparent that other adaptations and modifications may be made without departing from the scope of the following claims.

:1 claim:

1. In a machine for making T-head nails from a continuous length of wire having a head width equal to the diameter of its shank, two gripping dies movable transversely toward and away from each other, a hammer die movable longitudinally toward the gripping dies, and two cutter dies mounted adjacent said gripping dies at the hammer die end thereof, said cutter dies being movable transversely toward and away from each other, said hammer die being movable from a position remote from said cutter dies to a position within said gripping dies, the adjacent face of each gripping die having a longitudinal groove thereon over a portion of its length and terminating a distance from the hammer die end thereof a dis tance greater than the thickness of the nail head, the portion of each of said adjacent die faces on the end adjacent said hammer die being recessed for a depth substantially equal to the depth of said groove and along said face for such a distance as to permit free metal ilow along said tace when the wire is upset by said hammer die, said gripping dies when in their inward position forming a T-shaped cavity with the head of the T-shaped cavity having a length on each side of the leg greater than the corresponding length of the nail head, said hammer die having a guide portion and a hammer portion, said guide portion extending beyond said hammer portion toward said gripping dies and having a cross sect-ion increasing from the gripping die end thereof to a maximum width substantially equal to the width of said cavity, said hammer portion having a transverse fiat surface at least as long as the head of said nail, said flat surface being in a plane parallel to the path of movement of said dies, said continuous length of wire being tf6d longitudinally toward said gripping dies from the end opposite said haminer die, said gripping dies being adapted to grip the wire therebetween in said iongitudinal grooves and said cutter dies being adapted to sever the gripped wire at the hammer die end of the gripping dies prior to longitudinal movement of said hammer die whereby movement of said hammer die into said cavity will form the head of said nail.

2. In a machine for making T-head nails from a continuous length of wire having a head width equal to the diameter of its shank, two gripping dies movable trans versely toward and away from each other, a hammer die movable longitudinally toward the gripping dies, said hammer die being movable from a position remote trom said cutter dies to a position within said gripping dies, and two cutter dies mounted adjacent said gripping dies at the hammer die end thereof, said cutter dies being movable transversely toward and away from each other, the adjacent face of each gripping die having a projection thereon extending toward the other die and terminating a distance from the hammer die end thereof a distance greater than the thickness of the nail head, each of said projections having a longitudinal groove therein extending the length thereof, the portion of each of said adjacent die faces on the end adjacent said hammer die being spaced from the outer surface of said projection a distance substantially equal to the depth of said groove, said gripping dies when in their inward position being adapted to grip the nail shank with the distance between their end faces above said projections being equal to the width of the nail head for such a distance as to permit free metal flow along said faces when the wire is upset by said hamrner die, said hammer die having a \guide portion and a hammer portion, said guide portion extending beyond said hammer portion toward said gripping dies and having a cross section increasing from the gripping die end thereof to a maximum width equal to the distance between said die faces on the end adjacent said hammer die when the gripping dies are in their inner position, said hammer portion having a transverse fiat surface at least as long as the head of said nail, said flat surface being in a plane parallel to the path of movement of said dies, said continuous length or wire being fed longitudinally toward said gripping dies from the end opposite said hammer die, 7

said gripping dies being adapted to 'grip the wire therebe tween in said longitudinal grooves and said cutter dies being adapted to sever the gripped wire at the hammer die end of the gripping dies prior to longitudinal movement of said hammer die whereby movement of said hammer die into the space between said portions of the die faces on the end adjacent said hammer die will form the head of said nail.

References Cited in the file of this patent UNITED STATES PATENTS 74,616 Shields Feb. 18, 1868 83,377 Gracey Oct. 27, 1868 290,912 Moore Dec. 25, 188-3 369,778 Davis Sept. 13, 1887 

1. IN A MACHINE FOR MAKING T-HEAD NAILS FROM A CONTINUOUS LENGTH OF WIRE HAVING A HEAD WIDTH EQUAL TO THE DIAMETER OF ITS SHANK, TWO GRIPPING DIES MOVABLE TRANSVERSELY TOWARD AND AWAY FROM EACH OTHER, A HAMMER DIE MOVABLE LONGITUDINALLY TOWARD THE GRIPPING DIES, AND TWO CUTTER DIES MOUNTED ADJACENT SAID GRIPPING DIES AT THE HAMMER DIE END THEREOF, SAID CUTTER DIES BEING MOVABLE TRANSVERSELY TOWARD AND AWAY FROM EACH OTHER, SAID HAMMER DIE BEING MOVABLE FROM A POSITION REMOTE FROM SAID CUTTER DIES TO A POSITION WITHIN SAID GRIPPING DIES, THE ADJACENT FACE OF EACH GRIPPING DIE HAVING A LONGITUDINAL GROOVE THEREON OVER A PORTION OF ITS LENGTH AND TERMINATING A DISTANCE FROM THE HAMMER DIE END THEREOF A DISTANCE GREATER THAN THE THICKNESS OF THE NAIL HEAD, THE PORTION OF EACH OF SAID ADJACENT DIE FACES ON THE END ADJACENT SAID HAMMER DIE BEING RECESSED FOR A DEPTH SUBSTANTIALLY EQUAL TO THE DEPTH OF SAID GROOVE AND ALONG SAID FACE FOR SUCH A DISTANCE AS TO PERMIT FREE METAL FLOW ALONG SAID FACE WHEN THE WIRE IS UPSET BY SAID HAMMER DIE, SAID GRIPPING DIES WHEN IN THEIR INWARD POSITION FORMING A T-SHAPED CAVITY WITH THE HEAD OF THE T-SHAPED CAVITY HAVING A LENGTH ON EACH SIDE OF THE LEG GREATER THAN THE CORRESPONDING LENGTH OF THE NAIL HEAD, SAID HAMMER DIE HAVING A GUIDE PORTION AND A HAMMER PORTION, SAID GUIDE PORTION EXTENDING BEYOND SAID HAMMER PORTION TOWARD SAID GRIPPING DIES AND HAVING A CROSS SECTION INCREASING FROM THE GRIPPING DIE END THEREOF TO A MAXIMUM WIDTH SUBSTANTIALLY EQUAL TO THE WIDTH OF SAID CAVITY, SAID HAMMER PORTION HAVING A TRANSVERSE FLAT SURFACE AT LEAST AS LONG AS THE HEAD OF SAID NAIL, SAID FLAT SURFACE BEING IN A PLANE PARALLEL TO THE PATH OF MOVEMENT OF SAID DIES, SAID CONTINUOUS LENGTH OF WIRE BEING FED LONGITUDINALLY TOWARD SAID GRIPPING DIES FROM THE END OPPOSITE SAID HAMMER DIE, SAID GRIPPING DIES BEING ADAPTED TO GRIP THE WIRE THEREBETWEEN IN SAID LONGITUDINAL GROOVES AND SAID CUTTER DIES BEING ADAPTED TO SEVER THE GRIPPED WIRE AT THE HAMMER DIE END OF THE GRIPPING DIES PRIOR TO LONGITUDINAL MOVEMENT OF SAID HAMMER DIE WHEREBY MOVEMENT OF SAID HAMMER DIE INTO SAID CAVITY WILL FORM THE HEAD OF SAID NAIL. 